Package com.puppycrawl.tools.checkstyle.checks.coding

Class OneStatementPerLineCheck

java.lang.Object
com.puppycrawl.tools.checkstyle.AbstractAutomaticBean
com.puppycrawl.tools.checkstyle.api.AbstractViolationReporter
com.puppycrawl.tools.checkstyle.api.AbstractCheck
com.puppycrawl.tools.checkstyle.checks.coding.OneStatementPerLineCheck
All Implemented Interfaces:
Configurable, Contextualizable
public final class OneStatementPerLineCheck extends AbstractCheck
Checks that there is only one statement per line.

Rationale: It's very difficult to read multiple statements on one line.

In the Java programming language, statements are the fundamental unit of execution. All statements except blocks are terminated by a semicolon. Blocks are denoted by open and close curly braces.

OneStatementPerLineCheck checks the following types of statements: block statements, variable declaration statements, import statements, assignment statements, expression statements, increment statements, object creation statements, 'for loop' statements, 'break' statements, 'continue' statements, 'return' statements, resources statements (optional).

Notes: Unnecessary semicolons are ignored.

Since:
5.3

  • Field Details

  • Constructor Details

  • Method Details

    • setTreatTryResourcesAsStatement

      public void setTreatTryResourcesAsStatement(boolean treatTryResourcesAsStatement)
      Setter to enable resources processing.
      Parameters:
      treatTryResourcesAsStatement - user's value of treatTryResourcesAsStatement.
      Since:
      8.23

    • getDefaultTokens

      public int[] getDefaultTokens()
      Description copied from class: AbstractCheck
      Returns the default token a check is interested in. Only used if the configuration for a check does not define the tokens.
      Specified by:
      getDefaultTokens in class AbstractCheck
      Returns:
      the default tokens
      See Also:

    • getAcceptableTokens

      public int[] getAcceptableTokens()
      Description copied from class: AbstractCheck
      The configurable token set. Used to protect Checks against malicious users who specify an unacceptable token set in the configuration file. The default implementation returns the check's default tokens.
      Specified by:
      getAcceptableTokens in class AbstractCheck
      Returns:
      the token set this check is designed for.
      See Also:

    • getRequiredTokens

      public int[] getRequiredTokens()
      Description copied from class: AbstractCheck
      The tokens that this check must be registered for.
      Specified by:
      getRequiredTokens in class AbstractCheck
      Returns:
      the token set this must be registered for.
      See Also:

    • beginTree

      public void beginTree(DetailAST rootAST)
      Description copied from class: AbstractCheck
      Called before the starting to process a tree. Ideal place to initialize information that is to be collected whilst processing a tree.
      Overrides:
      beginTree in class AbstractCheck
      Parameters:
      rootAST - the root of the tree

    • visitToken

      public void visitToken(DetailAST ast)
      Description copied from class: AbstractCheck
      Called to process a token.
      Overrides:
      visitToken in class AbstractCheck
      Parameters:
      ast - the token to process

    • leaveToken

      public void leaveToken(DetailAST ast)
      Description copied from class: AbstractCheck
      Called after all the child nodes have been process.
      Overrides:
      leaveToken in class AbstractCheck
      Parameters:
      ast - the token leaving

    • checkIfSemicolonIsInDifferentLineThanPrevious

      private void checkIfSemicolonIsInDifferentLineThanPrevious(DetailAST ast)
      Checks if statement of given semicolon is in different line than previous statement.
      Parameters:
      ast - semicolon to check

    • logViolation

      private void logViolation(DetailAST violationNode)
      Logs a violation at the given AST node.
      Parameters:
      violationNode - token at which violation occurred.

    • isValidStatement

      private boolean isValidStatement(DetailAST statementStart)
      Checks whether the current statement is placed on a separate line from the previous statement.
      Parameters:
      statementStart - token representing the start of the current statement
      Returns:
      true if the current statement starts on a different line than the previous statement; false otherwise

    • getStatementStart

      private static DetailAST getStatementStart(DetailAST ast)
      Returns the starting node of the statement, or the previous statement's start if the current one is an empty statement.
      Parameters:
      ast - the SEMI token.
      Returns:
      the start of the associated statement or the previous sibling.

    • checkResourceVariable

      private boolean checkResourceVariable(DetailAST currentStatement)
      Checks whether the current statement represents a valid resource declaration in a try-with-resources statement.
      Parameters:
      currentStatement - the statement to check
      Returns:
      true if the statement is a valid resource declaration; false otherwise.

    • getStartNodeInExpression

      private static DetailAST getStartNodeInExpression(DetailAST expression)
      Finds the leftmost leaf node in the given expression's subtree.
      Parameters:
      expression - EXPR node.
      Returns:
      the leftmost leaf DetailAST node

    • getLastNestedLeafNode

      private static DetailAST getLastNestedLeafNode(DetailAST startToken)
      Finds the last nested leaf node.
      Parameters:
      startToken - start token of statement.
      Returns:
      the last nested leaf DetailAST node

    • isResource

      private static boolean isResource(DetailAST ast)
      Checks that given node is a resource.
      Parameters:
      ast - semicolon to check
      Returns:
      true if node is a resource